Update changelog.txt

Author: b-g

changelog.txt

@@ -6,6 +6,7 @@
 🏖😎 OpenMoji 17.0 - XX XXX 2026
 
 New:
+  + Yucatan and Queretaro flag @memburg #596
   + E070 extras-openmoji Bluesky by @agriyakhetarpal #557
   + E1DA extras-openmoji "ai hand" by @artlung Joe Crawford #561
   + 20E3 extras-openmoji combining enclosing keycap by @nataliakeniganti #565